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AmigaOS 4.0 - About OS4 - Preferences

COMPATIBILITY Preferences Editor
AmigaOS 4.0 utilises two different emulators; one is the successor of BlackBox emulation and is an interpretive emulator, thus the emulation speed is mediocre. On the other hand it has a very low "reaction time", and is ideal for time critical parts, such as interrupts. The other is Petunia, the "JIT emulator", which is a fast but less compatible way of emulation of the legacy Motorola processors. It is intended mainly for emulating applications, and therefore, when execution of the application leaves the bounds of the application's code segment, emulation falls back to the interpretive method, where it does its job and returns to the JIT emulation again.

Dynamic recompilation (also called just-in-time compilation or simply JIT compilation) is a technique of translating foreign processor machine code to native PPC machine code, "on the fly", and because of this can create a few subtle compatibility issues. Click here for more information about JIT.

The Compatibility Preferences editor enables/disables JIT emulation for specific programs or applications.

When the Compatibility Preferences editor is invoked it will display the following window:

JIT Emulator

Enables you to specify applications where the Just In Time (JIT) emulation can be enabled or disabled.

A tick in the box will result in 'Disabled' being displayed next to it and the application will not use JIT emulation.

Clicking on the box will result in the tick being removed and 'Enabled' being displayed next to it, so that JIT emulation can be used for the application.

If not specified here, JIT emulation will be used for all 68000 programs by default.

Blacklisted applications
Here you can add and remove programs from the list, or display information about programs in the list.

Add
Clicking on this button will bring up the following requester:

Simply highlight the application to be added to the list and click on OK.

Remove
Simply highlight the application to be removed from the list before clicking on the remove button.

Information
Clicking on this button willl display more information about the highlighted application:

Alternatively you can simply resize the original window to display information for all applications:

DOS

When you click on the gadget at the top of the window, the mode will change from 'JIT emulation' to 'DOS' and the window contents change:

Blacklisted applications
Now, rather than show configurable applications, it shows applications that are known to have issues when run under OS4.

However this list cannot be manually configured, hence the Add and Remove buttons are ghosted.

Information
Clicking on this button willl display more information about the highlighted application:

Alternatively you can simply resize the original window to display information for all applications:

Action Buttons
When you make changes you can choose to 'Save' them permanently, or you can 'Cancel' and lose all changes.

Return to Preferences Selection

Disclaimer: Amiga Auckland have prepared the above information for the use of its members based on our experiences and as such is subject to revision at any time. Amiga Auckland cannot guarantee any of the information and cannot be held accountable for any issues that may result from using it.

Copyright © 2006 Amiga Auckland Inc. All rights reserved.
Revised: February 9, 2006.